Laser FWD L4-1997cc 2.0L DOHC (1992)
Voltage:
Should exist
Osciloscope Test
OSCILLOSCOPE TEST
1. Connect scope pickup probe to the sensor terminal 1.
2. Warm engine to operating temperature and keep it running at 2,000 RPM, check the waveform on the scope. If scope pattern is not as depicted in
image, the sensor may be bad or there could be a fuel mixture problem. Refer to diagnosis by symptom for further system troubleshooting before
replacing the assembly.
HARNESS TEST
1. Disconnect the oxygen sensor and the ECU connector.
2. Using an Ohmmeter, check for continuity between the ECU harness connector terminal 4 and the oxygen sensor harness connector terminal 1.
Continuity:
Should exist.
3. Using an Ohmmeter, check for continuity (short) to ground between the ECU harness connector terminal 4 and the oxygen sensor harness connector
terminal 1.
Continuity:
Should not exist.
4. Using an Ohmmeter, check for continuity between the ECU harness connector terminal 106 and the oxygen sensor harness connector terminal 2.
Continuity:
Should exist.
5. Using an Ohmmeter, check for continuity between the oxygen sensor harness connector terminal 4 and ground.
Continuity:
Should exist.
If any of the previous tests produce unsatisfactory results, the harness will need to be repaired or replaced. Once repairs have been completed, clear
the trouble codes and road test the vehicle to confirm that the repair has corrected the problem and the code doesn't return.
If the same trouble code reoccurs, it is possible that there is an intermittent failure of the component or the ECU. Check for looseness at all harness
junctions and test for an intermittent failure.
